From the leader's perspective, the problem of learning to signal reduces to online decision-making with a finite action space in an adversarial environment, where the adversarial nature stems from the leader's unawareness of the follower's true type. Therefore, any no-regret learning algorithm, such as follow-the-leader [1]} and much broadly speaking, those based on Blackwell approachability [2]}, [3]}, can all be considered as a black-box in designing the learning algorithm. The following theorem is based on the seminal result regarding no-regret learning in the adversarial bandit problem [4]}.
